Wednesday, October 19, 2005

What the hell is going on with Tularemia? or, a Rant about public health problems

It's situations like this that really irk me.

I mentioned the tularemia detection in DC here almost 2 weeks ago, already annoyed that there hadn't been more information about it. There has been some discussion on the ProMed list, but it's hardly been a blip in the mainstream media. Yesterday, there was an article in Salon

The background:

On Sept. 24, 2005, tens of thousands of protesters marched past the White House and flooded the National Mall near 17th Street and Constitution Avenue. They had arrived from all over the country for a day of speeches and concerts to protest the war in Iraq. It may have been the biggest antiwar rally since Vietnam. A light rain fell early in the day and most of the afternoon was cool and overcast.

Unknown to the crowd, biological-weapons sensors, scattered for miles across Washington by the Department of Homeland Security, were quietly doing their work. The machines are designed to detect killer pathogens. Sometime between 10 a.m. on Sept. 24 and 10 a.m. on Sept. 25, six of those machines sucked in trace amounts of deadly bacteria called Francisella tularensis. The government fears it is one of six biological weapons most likely to be used against the United States.

Tularemia is a naturally-occurring, albeit rare, disease. The bacterium, Francisella tularensis, can infect a wide variety of animals, and can be spread in a number of ways: via ticks, contact with infected animals (this used to be a disease that was fairly common in hunters and trappers, and is nicknamed "rabbit fever"), drinking contaminated water, and airborne spread if the pathogen is aerosolized in some manner. (When I was first taking infectious disease epidemiology, it was mentioned that at least one pulmonary case was due to a rabbit puree which had been created when an infected rabbit was run over by a lawn mower. Similar cases in landscapers have been documented in Martha's Vineyard). It also is a potential biowarfare agent, due to the fact that it can spread fairly easily via aerosol, and that the infectious dose is incredibly low: as few as 10 inhaled organisms can cause disease.

So, when this bug was detected in 6 sensors in our nation's capital, at the same time as a large march in the area, wouldn't you think that would be some headline news? Hell, at least the second section?

Yet it's barely a blip on the nation's radar. Even many infectious disease folks I've spoken to haven't heard of it, and certainly the public at large is largely ignorant that anything happened. And that would be fine--I understand very well the conflicting desire to inform people about what was detected by the sensors, and at the same time, to educate them about how the tests work, the false positive rate, and other issues so that no one freaks out about something that may turn out to be a false alarm. But some of the revelations in this article are stunning. For example:

The DHS scrambled for three days to confirm just what may have been in the air that day. On Sept. 27, it turned for help to the Centers for Disease Control and Prevention. The CDC did its own tests, and on Sept. 30 -- six days after the deadly pathogens set off the sensors and well into the incubation period for tularemia -- alerted public health officials across the country to be on the lookout for tularemia, the deadly disease caused by F. tularensis.

"It is alarming that health officials ... were only notified six days after the bacteria was first detected," House Government Reform chairman Tom Davis, R-Va., wrote in an Oct. 3 letter to Homeland Security Secretary Michael Chertoff. "Have DHS and CDC analysts been able to determine if the pathogen detected was naturally occurring or the result of a terrorist attack?"

(Emphasis mine) 6 days for notification of health officials? These are the very people who should be warned ASAP. They should, theoretically, have some training in bioterrorist events, and know that in the early stages, it's pretty unlikely that a positive sensor means a bioterrorist attack, so the "public fear" issues that may keep some reporters from holding a story back shouldn't apply there. It should have been especially critical to notify them, as people from all over the country had flocked to the peace rally right where all those detectors went off. Luckily, tularemia isn't spread person-to-person, but the local health departments should have at least been put on alert to keep an eye out for potential cases.

Moving on,

"It is not unreasonable that this is a natural occurrence," says Von Roebuck, spokesman for the CDC. "There are still no cases of tularemia."

I'll discuss his "no cases" assertion a bit later, but regarding the naural occurrence scenario, sure, it's not totally unreasonable. I've seen estimates from 150,000 to 300,000 people involved in the September rally; lots of people around, kicking up dust. Would it be enough, though, and is tularemia even present in D.C.? Ideally, when any environmental sensors of this type are installed, the background levels of contamination should be determined first, so you know how much "noise" there is in the environment. I don't know if this was done with tularemia in D.C. (though I have to say, I doubt it). Had it been, we could already have data on the presence of naturally-occurring tularemia there. For instance, there certainly are a lot of squirrels in that area, and tularemia may be endemic in them. Testing of the rodent population there could further that hypothesis. One could also look at the molecular epidemiology of the pathogen population to see if the strain(s?) of tularemia isolated from the sensors matched up with ones found naturally in D.C. I'd assume some of this is being done now--at least, I hope it is.

BUT--according to the Salon article, those marchers would have to have been kickin' up some major dust:

There was another troubling thing. One of the sensors that went off was located at the Lincoln Memorial on the far western end of the Mall. Another was located near Judiciary Square, roughly two miles to the east and two blocks north of the Mall. A third was at the Army's Fort McNair, more than two miles from the Lincoln Memorial down the Potomac River past the Mall, on the point of land where the Washington Channel and Anacostia River meet. The locations of the other three sensors have not been disclosed.

It seems pretty unlikely that the soil could have been that contaminated, yet they'd never had a sensor pick this up before.

As far as the earlier assertion that there haven't been any cases, well, maybe there have, maybe not. Tularemia is also one of those pathogens that causes a "flu-like illness:" fever, chills, headache, muscle aches, cough, and weakness, with serious cases progressing to pneumonia and respiratory failure. It's very treatable with antibiotics, so it's certainly possible that many people have simply gone to their physician and were treated without ever having the causative pathogen isolated. The Salon article found several people who reported symptoms similar to those caused by F. tularensis; some went to the doctor, at least one did not. Had more been made of this in the national media, perhaps more people would have checked in with their physicians, and we could at least have samples to test for the bacterium. As it stands now, we don't know whether people were really infected, or not; and if they were, whether it was due to an actual terrorist event, or not.

The cuts are independent of the concern for influenza. They are a consequence of the wrecking-ball policies of the Bush Administration and the Republican-controlled congress (and shame to the democrats who helped). You don't stop a wrecking-ball in mid-swing. It has too much inertia and will continue to destroy critical infrastructure even as bandaids like supplementary avian flu funding try to cover the worst of the damage.

It's not just public health. It's dams, bridges, levees, the shredded safety-net for our most vulnerable neighbors. While pursuing military adventures abroad and obsessed with terrorists at home, the BushCo's left us defenseless and dangerously vulnerable in our own homes, workplaces and communities.

(Emphasis mine). And that's exactly the problem. We keep hearing over and over how we're "fighting the terrorists" and "taking the war to them," yada yada yada, yet we may have just been attacked in our own national capital with a real WMD, and no one's paying attention. All the attention to avian flu has been great, but the Powers That Be really need to wake up and realize that if they really want to do something to increase our safety, they should be investing more money here at home in better public health programs that will benefit everyone, instead of throwing some money here and there at different hot topics and hoping that will make them go away--it's crystal clear that's simply not working.

About me

I'm Tara C. Smith

From Iowa, United States

I'm a mom and a scientist, your basic stressed-out, wanna-have-it-all-and-do-it-all Gen Xer. Recently transplanted from Ohio to Iowa, I've spent most of my life in the midwest (with 4 years of college spent out east in "soda" territory). My main interest, and the subject of my research, is infectious disease: how does the microbe cause illness? What makes one strain nasty, and another "avirulent?" Are the latter really not causing any disease, or could some of those be possible for the development of chronic disease years down the road?
Additionally, I've spent a lot of time discussing the value of teaching evolution, and educating others about "intelligent design" and other forms of creationism. My interest in history of science and medicine is also useful as a way to tie all of the above interests together.
[Disclaimer: the views here are solely my own, and do not represent my employer, my spouse, that guy who's always sitting by the fountain when I come into work, or anyone else with whom I may be remotely affiliated.]